Nov. IS, 1919 



Nature and Control of Apple-Scald 



215 



favorable effect upon apple scald. The results of these and earlier 

 experiments show, however, that it is possible to use carbon dicxid as 

 an agency for reducing apple scald and that this can be accomplished 

 without evident injury to the apple. 



While it seems to have been conclusively proved that carbon dioxid is 

 not responsible for the occurrence of apple scald, it does not follow that 

 high percentages of the gas in storage air are to be looked upon with 

 favor, for such a condition would indicate a lack of air movement and 

 an accumulation of other gaseous products of the apple as well as of 

 carbon dioxid. 



Artificial scald. — Various attempts have been made to produce 

 apple-scald artificially or to shorten its period of development by chang- 

 ing the composition of the air; but, as mentioned in the discussions of 

 humidity and carbon dioxid, these have usually met with failure. Other 

 experiments of this sort were made with alcohols, acids, and esters. In 

 the preHminary tests the various substances w^re used in full strength 

 and were placed in close proximity to the fruit, but this led to such 

 serious and rapid injury from the more active agents that nothing 

 resembling scald was produced. In the later experiments dilutions were 

 made as indicated below, and the liquids were placed in the bottom of 

 8-liter jars with the apples supported in the top at a distance of approxi- 

 mately 12 inches from the chemicals. Twenty-five cc, of the material 

 were used in each jar. All the jars were loosely stoppered. The 

 experiments were made at 10° C. The results reported below are based 

 on the appearance of the apples after they had been removed from the 

 storage condition and had stood in a warm laboratory for 24 hours. 



Table II. — Effects of various volatile substances on Yellow Newtown and Rome Beauty 



apples 



Substances used. 



Effects. 



Water, control 



Ethyl alcohol 



Acetic acid 



Alcohol 60 per cent, acetic 

 acid 40 per cent. 



Alcohol, 90 per cent, acetic 

 acid, 10 per cent. 



Formic acid 100 per cent. 



Apples stored over water developed no scald or other 

 injury. 



At the end of 3 weeks no scald had developed, and 

 the apples were apparently still normal. 



Rome Beauty apples showed injury at the end of 24 

 hours, but the effects did not resemble scald. 



Rome Beauty apples had their flesh killed and 

 browned to a depth of yi inch at the end of 48 

 hours, but the effects did not resemble scald. 



At the end of 7 days dead brown areas of various 

 patterns were scattered over the skin of the apple. 

 Many of the smaller spots were located at the lenti- 

 cels. There was a clear-cut margin between the 

 diseased and the healthy areas, and the flesh was 



. affected to a much greater depth than it would be 

 by scald. The brown spots were as common on 

 the highly colored portions of the skin as on the 

 poorly colored ones. There was but slight re- 

 semblance to typical scald. 



No scald or other injury after 3 weeks. 



